powerpc/pseries: Fix kexec on recent firmware versions

Recent versions of firmware will fail to unmap the virtual processor
area if we have a dispatch trace log registered. This causes kexec
to fail.

If a trace log is registered this patch unregisters it before the
SLB shadow and virtual processor areas, fixing the problem.

The address argument is ignored by firmware on unregister so we
may as well remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/pseries/plpar_wrappers.h b/arch/powerpc/platforms/pseries/plpar_wrappers.h
index 4bf2120..a6921ae 100644
--- a/arch/powerpc/platforms/pseries/plpar_wrappers.h
+++ b/arch/powerpc/platforms/pseries/plpar_wrappers.h
@@ -73,9 +73,9 @@
 	return vpa_call(0x3, cpu, vpa);
 }
 
-static inline long unregister_dtl(unsigned long cpu, unsigned long vpa)
+static inline long unregister_dtl(unsigned long cpu)
 {
-	return vpa_call(0x6, cpu, vpa);
+	return vpa_call(0x6, cpu, 0);
 }
 
 static inline long register_dtl(unsigned long cpu, unsigned long vpa)